This invention relates to a ventilator for drawing and discharging air, and more particularly to a ventilator provided with a filter for cleaning atmospheric air to be taken into the room.
A conventional ventilator for drawing and discharging air at the same time is of the type which takes air directly into the room through the air-intake passage. Therefore, the conventional ventilator is accompanied with the drawback that various dust particles such as sand and cement contained in the air or cedar pollens depending on the season are drawn indoors, a condition detrimental to the human health. These events pose great problems to a family suffering from hay fever or irritation from roadway dust. Recently, it has been proposed to arrange a filter to the air-intake passage of a ventilator in order to remove dust and pollen floating in the air.
With the proposed type of ventilator, the ventilating capacity itself is not obstructed even if the quantity of drawn air and that of discharged air get out of balance. The reason is as follows. Quantities of air corresponding to a difference between the amount of drawn air and that of discharged air flow into or out of the room through the various gaps or crevices. Where, however, the amount of discharged air exceeds that of incoming air, the outside air flows indoors through the room crevices. Even though, therefore, the air-intake passage of the ventilator is fitted with a filter for the object of eliminating dust particles or pollens contained in the atmosphere, the external air streams contaminated with the above-mentioned foreign matters tend to be directly carried indoors without being strained by the filter. Therefore, the conventional ventilator lacks the effect of providing a filter.